Thermoplastic copolyester elastomers have gained acceptance in many fields because of their outstanding physical properties which are unique in relation to other thermoplastic polymers. However, copolyester elastomers are flammable and this limits their usefulness for preparing electrical parts, wire coverings, optical fiber-outer jacketing and other applications where fire retardant materials are needed.
Numerous halogenated organic compounds either alone or in combination with antimony trioxide have been tested or even recommended for use in polyester homopolymers or random copolyesters. Because of the relatively high flammability of multi-block copolyester elastomers, the ease with which such elastomers can be degraded, and the difficulty of retaining the elastomeric character of the multi-block elastomers in the presence of significant amounts of added materials, there still is a need for fully acceptable fire retardant multi-block copolyester elastomer compositions. The present invention provides flame retardant copolyester elastomer compositions which do not exhibit degradation and which substantially retain the elastomeric character of the starting polymer. Moreover, these compositions are substantially nondripping when burned.